“I would never put it in the power of any printer or publisher to suppress or alter a work of mine, by making him master of the copy” Thomas Paine, Rights of Man, 1792.
“The printer dares not go beyond his licensed copy” Milton, Aeropagetica, 1644.
Since time immemorial, unauthorized use and outright piracy of proprietary source material has been a source of lost revenue, confusion, and artistic corruption.
These historical problems have been compounded by the advent of digital technology. With it, the technology of copying materials and redistributing them in unauthorized manners has reached new heights of sophistication, and more importantly, omnipresence. Lacking objective means for comparing an alleged copy of material with the original, owners and litigation proceedings are left with a subjective opinion of whether the alleged copy is stolen, or has been used in an unauthorized manner. Furthermore, there is no simple means of tracing a path to an original purchaser of the material—something which can be valuable in tracing where a possible “leak” of the material first occurred.
A variety of methods for protecting commercial material have been attempted. One method is to embed information in the document or image that is imperceptible to the human eye and which is copied into reproductions. The embedded information includes data that permits the copyright owner to discern copies from the original so that illegal copying is detected.
Although the presently known and utilized media having steganography and methods using steganography are satisfactory, they include drawbacks. One such drawback is that, upon copying the reproduced copy over and over again, the embedded data may become degraded so that the data is not decodable. Another drawback is that image processing, such as scaling, rotation and the like, may also degrade the embedded data so that it is not decodable. Another drawback is that exact copies of images containing steganographic data reproduce that information as well as the original so that copies cannot easily be distinguished from the original by the presence of the steganographic mark. While the presence of the steganographic mark authenticates the original as legitimate and prevents the creation of an altered copy of the original, it does not distinguish between an exact copy of the original and the original itself.
Consequently, a need exists for a form of embedded data which is not reproduced in photocopies so that all subsequent copies (i.e., those which do not contain the unreproducable embedded data) are identifiable as photocopies so that fraudulent photocopies are easily detected. It is noted that this is the inverse of the currently known embedded steganography which passes the embedded data to photocopies.